WASHINGTON (Reuters) -The United States on Wednesday issued hundreds of fresh sanctions targeting Russia over the war in Ukraine in action that took aim at Moscow's circumvention of Western measures, including through China.

The U.S. Treasury Department imposed sanctions on nearly 200 targets and the State Department designated more than 80 in one of the most wide-ranging actions against Chinese companies so far in Washington's sanctions aimed at Russia.

The U.S. imposed sanctions on 20 companies based in China and Hong Kong, following repeated warnings from Washington about China's support for Russia's military, including during recent trips by Treasury Secretary Janet Yellen and U.S. Secretary of State Antony Blinken to the country.

China's support for Russia is one of the many issues threatening to sour the recent improvement in relations between the world's biggest economies.

"Treasury has consistently warned that companies will face significant consequences for providing material support for Russia's war, and the U.S. is imposing them today on almost 300 targets," Yellen said in a statement.

Russia's and China's embassies in Washington did not immediately respond to requests for comment.

The United States and its allies have imposed sanctions on thousands of targets since Russia invaded neighboring Ukraine. The war has seen tens of thousands killed and cities destroyed.

Washington has since sought to crack down on evasion of the Western measures, including by issuing sanctions on firms in China, Turkey and the United Arab Emirates.

Treasury's action on Wednesday sanctioned nearly 60 targets located in Azerbaijan, Belgium, China, Russia, Turkey, the United Arab Emirates and Slovakia it accused of enabling Russia to "acquire desperately-needed technology and equipment from abroad."

The move included measures against a China-based company Treasury said exported items for the production of drones - such as propellers, engines and sensors - to a company in Russia. Other China and Hong Kong-based technology suppliers were also targeted.

The State Department also imposed sanctions on four China-based companies it accused of supporting Russia's defense industrial base, including by shipping critical items to entities under U.S. sanctions in Russia, as well as companies in Turkey, Kyrgyzstan and Malaysia that it accused of shipping high priority items to Russia.

"The concern about entities in the PRC supplying Russia's war is in focus at the highest levels of the Department and the administration. The reason is very simple: the PRC is the leading supplier of critical components for Russia's defense industrial base, and Russia is using them to prosecute its war on Ukraine," a senior State Department official said.

"If the PRC were to end its support for exporting these items, Russia would struggle to sustain its war effort."

The Treasury also targeted Russia's acquisition of explosive precursors needed by Russia to keep producing gunpowder, rocket propellants and other explosives in Wednesday's action, including through sanctions on two China-based suppliers sending the substances to Russia.

CHEMICAL WEAPONS, FUTURE ENERGY

The U.S. also accused Russia of violating a global ban on chemical weapons.

The State Department also expanded its targeting of Russia's future ability to ship liquefied natural gas, or LNG, one of the country's top exports.

It designated two vessel operators involved in transporting technology including gravity based structure equipment, or concrete legs that support offshore platforms, for Russia's Arctic LNG 2 project. Previous U.S. sanctions on Arctic LNG 2 last month forced Novatek, Russia's largest LNG producer, to suspend production at the project which suffered a shortage of tankers to ship the fuel.

Also targeted were subsidiaries of Russia's state nuclear power company Rosatom as well as 12 entities within the Sibanthracite group of companies, one of Russia's largest producers of metallurgical coal, the State Department said.

Washington also imposed sanctions on Russian air carrier Pobeda, a subsidiary of Russian airline Aeroflot.

The U.S. Commerce Department has previously added more than 200 Boeing and Airbus airplanes operated by Russian airlines to an export control list as part of the Biden administration's sanctions over the Russian invasion of Ukraine.

NAVALNY

The State Department also targeted three people in connection to the death of late Russian opposition leader Alexei Navalny, the best known domestic critic of President Vladimir Putin, who died in February in a Russian Arctic prison.

Russian authorities say he died of natural causes. His followers believe he was killed by the authorities, which the Kremlin denies.

Wednesday's action targeted the director of the correctional colony in Russia where Navalny was held for the majority of his imprisonment, as well as the head of the solitary confinement detachment and the head of the medical unit at the colony where he was imprisoned before his death.

The officials oversaw the cells where Navalny was kept in solitary confinement, the walking yard where he allegedly collapsed and died and Navalny's health, including in the immediate aftermath of his collapse, the State Department said.